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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2014 Siemens AG
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <device/pci.h>
#include <soc/baytrail.h>
#include <soc/pci_devs.h>
#include <soc/iosf.h>
#include <delay.h>
#include <soc/i2c.h>
/* Wait for the transmit FIFO till there is at least one slot empty.
* FIFO stall due to transmit abort will be checked and resolved
*/
static int wait_tx_fifo(char *base_adr) {
int i;
if (read32(base_adr + I2C_ABORT_SOURCE) & 0x1ffff) {
/* Reading back I2C_CLR_TX_ABRT resets abort lock on TX FIFO */
i = *((volatile unsigned int *)(base_adr + I2C_CLR_TX_ABRT));
return I2C_ERR_ABORT |
(*((unsigned int *)(base_adr + I2C_ABORT_SOURCE)) & 0x1ffff);
}
/* Wait here for a free slot in TX-FIFO */
i = I2C_TIMEOUT_US;
while ((!(*((volatile unsigned int *)(base_adr + I2C_STATUS)) & I2C_TFNF))) {
udelay(1);
if (!--i)
return I2C_ERR_TIMEOUT;
}
return I2C_SUCCESS;
}
/* Wait for the receive FIFO till there is at least one valid entry to read.
* FIFO stall due to transmit abort will be checked and resolved
*/
static int wait_rx_fifo(char *base_adr) {
int i;
if (read32(base_adr + I2C_ABORT_SOURCE) & 0x1ffff) {
/* Reading back I2C_CLR_TX_ABRT resets abort lock on TX FIFO */
i = *((volatile unsigned int *)(base_adr + I2C_CLR_TX_ABRT));
return I2C_ERR_ABORT |
(*((unsigned int *)(base_adr + I2C_ABORT_SOURCE)) & 0x1ffff);
}
/* Wait here for a received entry in RX-FIFO */
i = I2C_TIMEOUT_US;
while ((!(*((volatile unsigned int *)(base_adr + I2C_STATUS)) & I2C_RFNE))) {
udelay(1);
if (!--i)
return I2C_ERR_TIMEOUT;
}
return I2C_SUCCESS;
}
/* When there will be a fast switch between send and receive, one have
* to wait until the first operation is completely finished
* before starting the second operation
*/
static int wait_for_idle(char *base_adr)
{
int i;
volatile int status;
/* For IDLE, increase timeout by ten times */
i = I2C_TIMEOUT_US * 10;
status = *((volatile unsigned int *)(base_adr + I2C_STATUS));
while (((status & I2C_MST_ACTIVITY) || (!(status & I2C_TFE)))) {
status = *((volatile unsigned int *)(base_adr + I2C_STATUS));
udelay(1);
if (!--i)
return I2C_ERR_TIMEOUT;
}
return I2C_SUCCESS;
}
/** \brief Enables I2C-controller, sets up BAR and timing parameters
* @param bus Number of the I2C-controller to use (0...6)
* @return I2C_SUCCESS on success, otherwise error code
*/
int i2c_init(unsigned bus)
{
device_t dev;
int base_adr[7] = {I2C0_MEM_BASE, I2C1_MEM_BASE, I2C2_MEM_BASE,
I2C3_MEM_BASE, I2C4_MEM_BASE, I2C5_MEM_BASE,
I2C6_MEM_BASE};
char *base_ptr;
/* Ensure the desired device is valid */
if (bus >= ARRAY_SIZE(base_adr)) {
printk(BIOS_ERR, "I2C: Only I2C controllers 0...6 are available.\n");
return I2C_ERR;
}
base_ptr = (char*)base_adr[bus];
/* Set the I2C-device the user wants to use */
dev = dev_find_slot(0, PCI_DEVFN(I2C1_DEV, bus + 1));
/* Ensure we have the right PCI device */
if ((pci_read_config16(dev, 0x0) != I2C_PCI_VENDOR_ID) ||
(pci_read_config16(dev, 0x2) != (I2C0_PCI_DEV_ID + bus))) {
printk(BIOS_ERR, "I2C: Controller %d not found!\n", bus);
return I2C_ERR;
}
/* Set memory base */
pci_write_config32(dev, PCI_BASE_ADDRESS_0, (int)base_ptr);
/* Enable memory space */
pci_write_config32(dev, PCI_COMMAND,
(pci_read_config32(dev, PCI_COMMAND) | 0x2));
/* Set up some settings of I2C controller */
*((unsigned int *)(base_ptr + I2C_CTRL)) = (I2C_RESTART_EN |
(I2C_STANDARD_MODE << 1) |
I2C_MASTER_ENABLE);
/* Adjust frequency for standard mode to 100 kHz */
/* The counter value can be computed by N=100MHz/2/I2C_CLK */
/* Thus, for 100 kHz I2C_CLK, N is 0x1F4 */
*((unsigned int *)(base_ptr + I2C_SS_SCL_HCNT)) = 0x1f4;
*((unsigned int *)(base_ptr + I2C_SS_SCL_LCNT)) = 0x1f4;
/* For 400 kHz, the counter value is 0x7d */
*((unsigned int *)(base_ptr + I2C_FS_SCL_HCNT)) = 0x7d;
*((unsigned int *)(base_ptr + I2C_FS_SCL_LCNT)) = 0x7d;
/* Enable the I2C controller for operation */
*((unsigned int *)(base_ptr + I2C_ENABLE)) = 0x1;
printk(BIOS_INFO, "I2C: Controller %d enabled.\n", bus);
return I2C_SUCCESS;
}
/** \brief Read bytes over I2C-Bus from a slave. This function tries only one
* time to transmit data. In case of an error (abort) error code is
* returned. Retransmission has to be done from caller!
* @param bus Number of the I2C-controller to use (0...6)
* @param chip 7 Bit of the slave address on I2C bus
* @param addr Address inside slave where to read from
* @param *buf Pointer to the buffer where to store read data
* @param len Number of bytes to read
* @return I2C_SUCCESS when read was successful, otherwise error code
*/
int i2c_read(unsigned bus, unsigned chip, unsigned addr,
uint8_t *buf, unsigned len)
{
int i = 0;
char *base_ptr = NULL;
device_t dev;
unsigned int val;
int stat;
/* Get base address of desired I2C-controller */
dev = dev_find_slot(0, PCI_DEVFN(I2C1_DEV, bus + 1));
base_ptr = (char *)pci_read_config32(dev, PCI_BASE_ADDRESS_0);
if (base_ptr == NULL) {
printk(BIOS_INFO, "I2C: Invalid Base address\n");
return I2C_ERR_INVALID_ADR;
}
/* Ensure I2C controller is not active before setting slave address */
stat = wait_for_idle(base_ptr);
if (stat != I2C_SUCCESS)
return stat;
/* Now we can program the desired slave address and start transfer */
*((unsigned int *)(base_ptr + I2C_TARGET_ADR)) = (chip & 0xff);
/* Send address inside slave to read from */
*((unsigned int *)(base_ptr + I2C_DATA_CMD)) = (addr & 0xff);
/* For the next byte we need a repeated start condition */
val = I2C_RW_CMD | I2C_RESTART;
/* Now we can read desired amount of data over I2C */
for (i = 0; i < len; i++) {
/* A read is initiated by writing dummy data to the DATA-register */
*((unsigned int *)(base_ptr + I2C_DATA_CMD)) = val;
stat = wait_rx_fifo(base_ptr);
if (stat)
return stat;
buf[i] = (*((unsigned int *)(base_ptr + I2C_DATA_CMD))) & 0xff;
val = I2C_RW_CMD;
if (i == (len - 2)) {
/* For the last byte we need a stop condition to be generated */
val |= I2C_STOP;
}
}
return I2C_SUCCESS;
}
/** \brief Write bytes over I2C-Bus from a slave. This function tries only one
* time to transmit data. In case of an error (abort) error code is
* returned. Retransmission has to be done from caller!
* @param bus Number of the I2C-controller to use (0...6)
* @param chip 7 Bit of the slave address on I2C bus
* @param addr Address inside slave where to write to
* @param *buf Pointer to the buffer where data to write is stored
* @param len Number of bytes to write
* @return I2C_SUCCESS when read was successful, otherwise error code
*/
int i2c_write(unsigned bus, unsigned chip, unsigned addr,
const uint8_t *buf, unsigned len)
{
int i;
char *base_ptr;
device_t dev;
unsigned int val;
int stat;
/* Get base address of desired I2C-controller */
dev = dev_find_slot(0, PCI_DEVFN(I2C1_DEV, bus + 1));
base_ptr = (char *)pci_read_config32(dev, PCI_BASE_ADDRESS_0);
if (base_ptr == NULL) {
return I2C_ERR_INVALID_ADR;
}
/* Ensure I2C controller is not active yet */
stat = wait_for_idle(base_ptr);
if (stat) {
return stat;
}
/* Program slave address to use for this transfer */
*((unsigned int *)(base_ptr + I2C_TARGET_ADR)) = (chip & 0xff);
/* Send address inside slave to write data to */
*((unsigned int *)(base_ptr + I2C_DATA_CMD)) = (addr & 0xff);
for (i = 0; i < len; i++) {
val = (unsigned int)(buf[i] & 0xff); /* Take only 8 bits */
if (i == (len - 1)) {
/* For the last byte we need a stop condition */
val |= I2C_STOP;
}
stat = wait_tx_fifo(base_ptr);
if (stat) {
return stat;
}
*((unsigned int *)(base_ptr + I2C_DATA_CMD)) = val;
}
return I2C_SUCCESS;
}
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